1. Field of the Invention (Technical Field)
The present invention relates to the general field of surgical irrigants, and in particular biologically enhanced irrigant solutions. Irrigant solutions are provided that include biologically active chemical structures and fluids that attach, by any means, to specific tissue types, or that additionally or alternatively provide release of specific compounds, components or elements that enhance surgical tool performance. The elements described herein may be employed in any surgical procedure utilizing irrigation as a means of wetting tissue to help maintain viability, distension of a working space, enhance visualization, enhance surgical tool performance, provide tissue nutrients, or the like, including specifically surgical procedures involving the articular joints in which irrigants are used as a distension and visualization medium.
2. Background Art
Note that the following discussion refers to a number of publications by author(s) and year of publication, and that due to recent publication dates certain publications are not to be considered as prior art vis-a-vis the present invention. Discussion of such publications herein is given for more complete background and is not to be construed as an admission that such publications are prior art for patentability determination purposes.
To date surgical irrigants have primarily focused on providing a “lavage” mode of use. Fluids for such purposes have been selected from organically based solutions designed to minimize water extravasation in those instances where the fluid is used as distension medium. Hydrostatic pressure and osmotic pressure are typically balanced to prevent excess water absorption or loss by tissue. As a result, during endoscopic procedures, the dominant majority of fluids are aimed at providing a transparent medium for visualization. U.S. Pat. No. 4,504,493, to Marshall et al., discloses a solution composed of glycerol and water, that is non-cytotoxic, non-hemolytic, non-viscid, non-conductive and optically clear.
For arthroscopic surgery, irrigants are disclosed that are hypertonic solutions, such as the solution disclosed in U.S. Pat. No. 4,872,865 to Bloebaum et al. The aqueous solution of U.S. Pat. No. 4,872,865 contains ions of sodium, chlorine, potassium and calcium, and the solution may be employed as an irrigant in arthroscopic surgery to reduce the risk of swelling and injury of the synovial tissues, and as a therapeutic treatment for swelling and inflammation. This is done, in part, by establishing an osmotic gradient that will tend to cause water and water soluble inflammatory products to be drawn out of the cells and tissues.
Other irrigant solutions are also known that contain a variety of salts, including sodium, calcium, potassium or magnesium. Thus electrolyte solutions are known, such as Ringer's solution, a combination of sodium, calcium and potassium ions with sodium lactate, and a variety of balanced salt solutions, many of which employ buffering systems. Also known are other solutions, such as those containing glutathione, sodium bicarbonate, dextrose and the like. For example, U.S. Pat. No. 5,304,724 to Newton discloses a formulation for and method of making certain such solutions.
It is also known to employ a local anesthetic as a component of an electrolyte solution administered by irrigation, such as that disclosed in U.S. Pat. No. 4,938,970 to Hustead et al. In U.S. Pat. No. 4,938,970 a buffered electrolyte salt solution is provided, the electrolytes present at a concentration where they do not cause pain, and further optionally including one or more local anesthetics, such as lidocaine, medivacaine, bupivacaine and the like.
Other irrigation solutions are known that can be employed to both inhibit pain and inflammation. Thus U.S. Pat. No. 5,820,583 to Demopulos et al. discloses a solution, such as saline or lactated Ringer's solution, that contains components such as a serotonin2 antagonist, a serotonin3 antagonist, a histamine antagonist, a serotonin agonist, a cyclooxygenase inhibitor, a neurokinin1 antagonist, an ATP-sensitive potassium channel opener, a calcium channel antagonist, a bradykinin1 antagonist, a bradykinin2 antagonist and a μ-opioid agonist. The multiple components are in low concentrations, and are directed at local inhibition of mediators of pain, inflammation, spasm and restenosis in a physiologic electrolyte carrier fluid. In a related patent, U.S. Pat. No. 5,860,950 also to Demopulos et al., methods of inhibiting pain and inflammation during arthroscopic surgery procedures, by delivery of multiple components as described, are described and claimed.
Irrigant solutions are thus employed which have limited therapeutic benefit, principally the inhibition of pain, and secondarily the inhibition of inflammatory processes and responses. There is a need for systems and solutions that may be employed to effect more than a single therapeutic purpose, including irrigant solutions that provide for desired distension and clearing of visual fields, as in arthroscopic surgery, and that also provide a desired therapeutic benefit.